1. Field of Invention
The field of the currently claimed embodiments of this invention relates to electronic sensors, devices and circuits, and more particularly to electronic sensors, devices and circuits for sensing fluids.
2. Discussion of Related Art
Organic conductors and semiconductors have been harnessed for the detection of an enormous variety of molecular vapors (Someya, T., Dodabalapur, A., Huang, J., See, K. C. & Katz, H. E. Adv. Mater. 22, 3799-3811 (2010); Locklin, J. & Bao, Z. Anal Bioanal Chem 384, 336-342 (2006); Yang, W. et al. in Angew. Chem. Int. Ed. Vol. 49 2114-2138 (2010)), small molecules in solution (Locklin, J. & Bao, Z. Anal Bioanal Chem 384, 336-342 (2006); Roberts, M. E. et al. P Natl Acad Sci Usa 105, 12134-12139 (2008)), biomolecules (Roberts, M. E. et al. P Natl Acad Sci Usa 105, 12134-12139 (2008); Guo, X., Gorodetsky, A. A., Hone, J., Barton, J. K. & Nuckolls, C. Nat Nanotechnol3, 163-167 (2008)), electromagnetic radiation (Campbell, I. H., Crone, B. K., Appl. Phys. Lett. 95, 263302 (2009)), temperature (Letizia, J. A., Rivnay, J., Facchetti, A., Ratner, M. A. & Marks, T. J. Adv Funct Mater 20, 50-58 (2010)), and mechanical force (Hsu, Y.-J., Jia, Z. & Kymissis, I. Ieee T Electron Dev 58, 910-917 (2011); Someya, T. et al. P Natl Acad Sci Usa 101, 9966-9970 (2004)). The transduction mechanism to an electronic signal can be a perturbation of the charge carrier distribution in response to chemical binding, reaction, absorption, or adsorption; a change in carrier energy levels, a change in dipole orientation, and/or a change in the carrier transport pathway between two electrodes (Someya, T., Dodabalapur, A., Huang, J., See, K. C. & Katz, H. E. Adv. Mater. 22, 3799-3811 (2010)). A rich variety of organic and carbon-based materials have been enlisted for this application, including conjugated organic molecules and polymers (Roberts, M. E., Mannsfeld, S. C. B., Stoltenberg, R. M. & Bao, Z. Org Electron 10, 377-383 (2009)), carbon nanotubes and graphene (Guo, X., Gorodetsky, A. A., Hone, J., Barton, J. K. & Nuckolls, C. Nat Nanotechnol3, 163-167 (2008); Huang, J. et al. in J. Mater. Chem. Vol. 20 2644 (2010); Harris, K. D. et al. J Phys Chem C 111, 17947-17951 (2007); Someya, T., Small, J., Kim, P., Nuckolls, C. & Yardley, J. Nano Lett 3, 877-881 (2003); Feldman, A. K., Steigerwald, M. L., Guo, X. & Nuckolls, C. Accounts Chem Res 41, 1731-1741 (2008)), and polymer composites (DiBenedetto, S. A., Facchetti, A., Ratner, M. A. & Marks, T. J. Adv Mater 21, 1407-1433 (2009)). However, the architecture aspect of these devices is still in the first stage, namely, so-called chemiresistors, chemicapacitors, and organic field-effect transistors (OFETs). To take advantage of the true potential of these devices, it is desirable to integrate these sensors into the information medium of electronics, which is binary. Digital or binary language is very powerful in that it allows engineers to interface basic organic sensors with existing electronics components to ultimately produce usable products. However, sensitivity and selectivity are two main areas that demand improvement for organic electronic sensors. Therefore, there remains a need for improved electronic sensors, devices and circuits for sensing fluids.